This invention relates to the preparation of partially hydrolyzed elastin. Elastin is the major component of elastic fibers found primarily in connective tissue in conjunction with collagen and polysaccharides. Major concentrations of elastin are found in blood vessels. Another source of elastin is in the ligaments and more particularly the ligamentum nuchae prominent in the necks of grazing animals and in their hides.
Elastin is known to have a highly distinctive amino acid composition. Although similar to collagen in that one-third of the amino acids residues are glycine, elastin is rich in proline and in contrast to collagen, elastin contains very little hydroxyproline, no hydroxylysine and is very low in polar amino acids. Elastin is very rich in nonpolar aliphatic residues such as isoleucine, leucine, valine and alanine. Elastin, as present in mature animals, is highly cross-linked, therefore, making it very difficult to solubilize. This dense cross-linking is attributable to the desmosine and isodesmosine residues which are highly functional and cross-link both intra- and interfibularly. It is believed that the desmosine and isodesmosine cross-linking gives the elastin fibers their elasticity. The desmosine residue can be represented by the structural formula: ##STR1## And the isodesmosine residue represented by the structural formula: ##STR2##
This highly cross-linked structure is extremely difficult to solubilize and purify, especially in the case of mature animals such as horses, cows, and the like, which are aged and thus contain elastin which has an extremely high cross-link density.
Prior art methods of solubilizing elastin primarily include the use of elastases to hydrolyze the peptide linkages to provide an acceptable product.
Solubilized elastin has found utility in the cosmetic and pharmaceutical fields. However, its manufacture has been limited to small quantities and it is not necessarily of acceptable purities because of the enzymatic residue required for the hydrolysis.
One particular method of producing elastin by nonenzymatic means is disclosed in "ELASTIN" by Berg et al., Cosmetics & Toiletries, Vol. 94, October, 1979.
In accordance with the present invention, a method of producing partially hydrolyzed elastin in pure form is provided without the need for enzymatic digestion and the removal of attendant residual enzymes in the predigest.